Computer aided engineering (CAE) has been used for supporting engineers in many tasks. For example, in a structure or product design procedure, CAE analysis, in particular finite element analysis (FEA), has often been employed to obtain simulated structural responses (e.g., stresses, displacements, etc.) under various loading conditions (e.g., static or dynamic).
As computer technologies improved over the past years, FEA models have become more sophisticated. For example, simulation results of modern FEA models are expected to accurately represent the center-of-mass not only for the complete vehicle, but for each part of the vehicle, such as the vehicle floorboard with carpet and fasteners attached. Likewise, all additional parts defining the vehicle, typically in the hundreds, are expected to be accurately modeled including their centers-of-mass. A prior art approach has been to model the mass of the carpet and fasteners as nodal masses and report kinetic energy from the simulation results separately for the nodal masses and the vehicle floor. Afterwards, the two kinetic energies are combined to obtain the total kinetic energy of the floorboard with carpet and fasteners. Another prior art approach defines a mass per unit area for the carpet layer over the vehicle floor, which then augments the mass of the part to account for the carpet layer. The latter approach is generally avoided since the center-of-mass of the part cannot be as accurately controlled as it can when defining nodal masses. Large vehicle models may contain well over 100,000 nodal lumped masses. The prior art approach is acceptable when all nodal masses used to augment the mass of the part belong to nodes that are unique to the part. In this case the summation of the lumped mass nodal kinetic energy and the part kinetic energy gives the kinetic energy value of interest to the designer; however, if a particular node k having a lumped mass shared by two or more parts, the kinetic energy calculations for the part will be too large since the entire lumped mass of node k and the resultant kinetic energy is added to the part kinetic energy. The latter is true for every part that shares node k. Generally, the kinetic energy calculations for parts are incorrect for every part in the model where a nodal lumped mass is attached to a part node shared by multiple parts. Another possible source of error in the kinetic energy calculation appears when an element of a part fails and is deleted or when an entire part is deleted. In this latter case, if the element has a node, which is assigned a lumped mass, the kinetic energy for the portion of the lumped mass attributed to the failed element or deleted part should be excluded from the kinetic energy of the part.
It would, therefore, be desirable to have computationally efficient methods and systems for automatically reporting correct kinetic energy of a part where a subset of nodes of the part receiving lumped masses are shared by one or more additional parts and when failed elements and deleted parts have attributed lumped mass.